System of control.



R. E. HELLMUND.

SYSTEM OF CONTROL.

APPLICATION FILED NOV. 25. 1914.

Patented J 11116 18, 19 18.

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"lllllllll n mu Wm H We E LL L 0 d u R AT.TORNEY R. E. HELLMUND. SYSTEMOF CONTROL.

APPLICATION FILED NOV. 25,1914.

1,269,601 Patented June 18, 1918. S

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WITNESSES: INVENTOR R d 1. EH N d.

u a; e mun K ATTQRNEY R. E. HELLMUND.

SYSTEM OF CONTROL.

APPLICATION FILED 940L251. 1914.

.1 ,269, 60 1 Patented J une 18, [918.

3 SHEETS-SHEET 3- Ground.

WITNESSES: INVENTOR' RudoQ EHeIImund.

' 2 ATTORNEY ing currents, the said source bein pluralit UNITED STATESPATENT oFrroE.

BUDOLF E. HELLIUND, OI PITTSBURGH, PENNSYLVANIA, ASSIGNOIB, TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

SYSTEM or CONTROL.

Specification of Letters ratent. Patented June 18, 1918.

Application med November 25,1914. Serial in. 373,917.

To all whom it may concerns Be it known that I, RUDOLF E. HELLMUN asubject of the German Empire, and a resident of Pittsburgh in the countyof Allegheny and State of Pennsylvania, have invented a new and usefulImprovement in Systems of Control, of which the following is aspecification.

My invention relates to systems of control, and it has special referenceto the auto- .matic acceleration of electric motors that are adapted topropel electric railway vehicles and the like.

The object of my invention is to provide a system of the above-indicatedcharacter which shall embody relatively simple means for automaticallyaccelerating'an electric motor in a smooth and efiicient manner, byincreasing the voltage applied to the motor terminals from a supplycircuit, upon a pre-,.

determined variation of motor torque.

The instantaneous torque exerted upon each armature conductor of anaccelerating motor :F=IBL 10- dynes, where I equals current in amperesin the conductor, B equals flux density in maxwells per squarecentimeter, and L equals length of conductor that is cut by the flux;or, in other words, since the length of active conductors in an armatureis a constant, the torque exerted by the entire motor armature issubstantially proportional to the armature current times the field fluxor. the field current which produces the flux. According to my presentinvention, I take advantage ofthe principles just recited by providingan auxiliary source of energy that is associated with the motor forfield control purposes to cause a difference in the value of thearmature and field windconnected either in parallel relation with thefield winding which is'disposed in series relation with the armature, orbeing connected to separately excite the field winding, and a switchingdevice or relay having a of actuating coils that are respectiveyenergized in proportion to the armature and field winding currents andare adapted'to jointly effect the actuation of the switching device toexclude from the circuit a translating device, such as. a resistor, apredetermined time after starting,

to increase the voltage that is applied to the motor from the supplycircuit, with the consequent motor acceleration. Inasmuch as arelatively heavy torque is usuall required for starting purposes,especially in series-connected railway motors, the switching devicereferred to will remain inoper ative withrespect to the main-circuittranslating device until the armature and the field-winding currentsdecrease to predetermined values to permit of the actuation of theswitching device. Automatic acceleration is thus effected in terms ofthe motor torque, so to speak, since the switching de vice is influencedby the resultant of the elect-ro-magnetic forces that are produced bythetwo actuating coils substantially in proportion to the torque exerted bythe motor.

Whereas the above remarks apply primarily to direct-current motors, thesame principles are of course applicable to alternating-current motorsrunning with the repulsion connection, or during the transition fromrepulsion to doubly-fed connection, where in either case, the armatureand main field-winding current are of different values. In such cases,it is also possible to compensate for phase displacement between thearmature and field current, as hereinafter described.

The relay coil corresponding to the field Winding may be energized inproportion to mature to energize one coil of the relay. It

will also be understood that, instead of using the heavy armature orfield current of alternating-current motors, small currentreducingtransformers maybe employed.

-In the accompanying drawing, Figure 1 is a diagrammatic View of asystem of control embodying my invention; Fig. 2 is a diagrammatic viewof the main circuit of a system illustrating a modified form of myinvention; Fig. 3 is a diagrammatic view of the auxiliary controlcircuits for governing the operation of the various motor-controllingswitches shown in Fig. 2 in a0- cordance with the sequence chart ofwellknown form that is illustrated in Fig. 4; Fi s. 5, 6 and 8illustrate modified systems embodying my invention; and Fig. 7 is anenlarged diagrammatic view of a portion of the apparatus shown in thesefigures.

Referring to F ig. l of the drawing, the system shown comprises asuitable supply circuit including conductors respectively marked Trolleyand Ground, an electric motor having an armature A and aseries-connected field magnet winding F, a main-circuit switch S, anaccelerating resistor AR that is adapted to be initially connected inthe main motor circuit, a switching device K for short-circuiting theresistor AR; a torque relay T that is associated with the motor windingsin a manner to be described; and a storage battery B which is variablyconnected in parallel-circuit relation with the field magnet winding Ffor purposes of field control, thereby providing means for governing themotor speed, in accordance with well-known principles.

The switching device or torque relay T is provided with an actuatingcoil 1 that is connected, through conductors 2 and 3, in series relationwith the resistor AR and the armature A, and a second actuating coil'dthat is connected, through conductors 5 and 5?, preferably in seriescircuit relation with the armature A and the field-magnet windmg F fordirect-current operation, andcpreferably in parallel-circuit rel-ationto the field'winding for alternating-current operation. The actuatingcoils 1 and i are adapt- I ed to coiiperatively act upon the core 6 oflit) the switching device T to maintain a movable contact member 7 outof engagement with a pair or stationary contact members 8 during theinitial starting period of the m0- tor, as hereinafterdescribed. Theswitching device K is of a familiar electrically-controlled type havingcoiiperating stationary and movable main-circuit contact members 9 and10, and an interlock T in its actuating coil circuit. familiar form thatis adapted to permit energization of the actuating coil through thecontact members 7 and 8 of the torque relay T when the switching deviceK occupies its lower or, in this case, open position, and that isadapted to permit direct energization of the actuating coil when thedevice K occupies its upper or, in this case, closed position, therebycompleting a holding circuit, as will be understood. The actuatingcoilof the switching device K may be supplied with energy from anyconvenient source, as from the trolley through a suitable controlresister CR, as shown in Fig. l, or from a I storage battery, asillustrated in Fig. 2.

v The switching device K, when closed, is adapted to short circuit theaccelerating re The interlock T is also of a armature A, conductor 14,where the circuit divides, one branch including conductor 5, relay coil4:, conductor 5, and the field-magnet winding F, and the other branchincluding a predetermined portion, preferably all, of the cells of thebattery B, in order to produce a relatively strong field'fiuri, acommonv circuit being completed through conductor 15 to ground.

The heavy rush of current when the motor is initially connected to thesupply circuit is sufficient to cause enough current to traverse theactuating coils 1 and 4C of the torque relay T to maintain it in itsupper or open position. However, as soon as the motor has acceleratedsomewhat and its counterelectromotive force has increased a certainamount, the armature and field-winding cur rents and, consequently, themotor torque, decrease to respectively predetermined values, and thetorque relay T is thereupon permitted to drop to its lower position,whereby the coiiperating contact members 7 and 8 engage to energize theactuating coil of the switching device K, and the resistor AB isshort-circuited, as already mentioned. The motor will thus be furtheraccelerated to a predetermined point whereupon, if desired, the numberof cells of the battery B that is connected in parallel relation withthe field winding F may be decreased to correspondingly reduce the fieldcurrent and correspondingly increase the motor speed. It will beobserved that, once the device K is closed, its holding circuit referredto above, maintains it closed, irrespective of further actuation of thetorque relay T.

Reference may now be had to Fig. 2 of the drawing, wherein is shown thesupply conductors, Trolley and Ground; the armature A and the fieldwinding F, which in this case, however, are not directly connected; theaccelerating resistor AR; the torque relay T; the switching device K; areversing switch RS, preferably of a familiar electromagneticallycontrolled type, for reversing the electrical relations of the armatureA conditions, and a second field winding MF" which is connected in shuntrelation to the armature MA. The auxiliary generator is provided with afield winding GrF that is connected in the main motor circuit and asecond field windin GrF that is connected in series with a fiel-regulating resistd r FR across the battery B The various sections ofthe resistor FR are respectively adapted to be short-circuited byswitches G Gr and G All of the switches shown, .with the exception ofthe main reversing switch RS,

the device K, and the torque relay T, which,

have already been described, are preferably of a familiarelectromagnetically controlled type, and no further description thereofis deemed to be necessary. I

Referring now to Fig. 3, the auxiliary control system shown comprises,in addition to the actuating coils of the various motor-controllingswitches and of the main.

reversing switch RS that are illustrated in Fig. 1, an auxiliary sourceof energy which may conveniently comprise the battery B, a mastercontroller that is adapted to occupy a plurality of successive operatingpositions a to 72,, inclusive, and a master reverser MR of a familiartype.

Assuming that the master reverser MR and the main reversing switch RSrespectively occupy their forward positions, and that the mastercontroller MO is moved to its first operating position a, the operationof the system under consideration may be set forth as follows: A circuitis first estab lished from one terminal of the battery B throughconductor 16, control finger 17, contact segments 18, 19 and 20 andcontrol finger 21 of the master controller, conductor 22, the actuatingcoil of the switch K and conductor 23 to the opposite terminal of thebattery B Other circuits are simultaneously established from energizedcontact segments 24 and 25 of the master controller, through controlfingers 26 and 27 and conductors 28 and 29, respectively, to theactuating coils of the switches X and X and thence to the negativeconductor 23.

If the master controller MC is then moved to its position b, a pluralityof energized contact segments 30, 31 and 32, respectively engage controlfingers 33, 34, and 35, from which points circuits are completed throughconductors 36, 37 and 38, respectively, to the actuating coils of theswitches G, G and G and the negative conductor 23.

It will be noted that the circuit-arrangements just described are allpreliminary to the actuating coil of the line switch LS and theconductor 23 to the negative battery terminal.

The torque relay T will be raised to its open position by the initialconnection of the main motor to the supply circuit, as described inconnection with Fig. 1, and will subsequently drop to its lower positionto effect short-circuit of .the resistor AR by the switching device K,as also described in connection with that figure.

When the resistor AR has been excluded from circuit, the mastercontroller MG may be moved to its position (I, whereby the contactsegment 30 disengages the control finger 33, and the switch G isconsequently opened. As the master controller is then moved to itspositions e and f, the switches G and G are also opened by reason of therespective disengagement of the control finger 34 and the contactsegment 31, and the control finger 35 and contact segment 32.

The field-regulating resistor FR is thus gradually inserted in thecircuit of the field winding GrF of the auxiliary generator, therebycausing a weakening of the generator field flux and, consequently,partially deenergizing the main field winding F to thereby effect anincrease in the main-motor speed, as will be understood.

7 If the master controller MG is then successively moved to itspositions 9 and h, the switches X and X are successively opened byreason of the disengagement of the con trol .fingers and contactsegments of the master controller that are included in their respectivecontrol circuits, thereby gradually inserting the auxiliary motor fieldwinding MF in the main field-winding circuit and causing it to beoperative upon the auxiliary motor armature MA. The auxiliarymotor-field flux being thus strengthened, the motor will run atcorrespondingly decreased speeds, thus again decreasing the excitationof the main field winding F and bringing about a further acceleration ofthe main motor.

Reference may now be had to Fig. 5 and Fig. 6, which disclose myinvention'as applied to the operation of single-phase mo-- tors, Fig. 5illustrates a method for automatically effecting the change in terms ofthe motor torque, from an initial connection as a repulsion motor to astraight series connection, while Fig. 6 shows a system forautomatically effecting the change from the series to a doubly-fedconnection. The system illustrated in Fig. 5 comprises a suit- I ablesupply circuit 41, to which is connected torque re an auto-transformerAT, in accordance with familiar practice; an alternating currentactuating coil of theswitching device K {under predetermined conditions,which contact members may be suitably mounted. on a drum 43 orotherwise, to be actuated by the torque relay T, as set .forth below.

The relay T best shown in Fig. 7, may

comprise an armature 44 that ismounted' upon a shaft 45 to which is alsosecured a suitable motor torque-opposing spring 46 on the drum or othermember 43 and a suitable exciting field winding 47 inasmuch asrelatively small rotative movement of the armature 44 occurs,current-collecting apparatus of the usual type may be omitted, and

the armature leads 48 and 49 ma be suitably flexibly connected directlyto t e armature winding. The armature 44, in the system of Fig. 5, isconnected in series relation with ill till

lit:

the motor armature A and is included in the initial short-circuitthereof by the switching device K 47 is shown coniiected in seriesrelation with the main .field winding F although a parallel connectionis preferable in some cases, as hereinafter set forth.

A. brief description of the operation of the system will be all that isnecessary. The motor is started as a repulsion motor, its armature beingshort-circuited in the manner shown, the initial torque of the relay Tbeing sufficient to overcome the spring 46 and maintain the contactmembers 42 opencircuited. When the main armature and main field-Winding.currents decrease to respectively predetermined values, the armature 44,its torque being correspondingly reduced, is rotated somewhat by thespring 46 to eilect engagement of the contact members 42, and thusenergize the actuating coil of the switchin device K to remove theshort-circuit rom the armature A thereby automatically efi'ecting thechan e from repulsion to series connection 0 the main motor.

The apparatus employed in the system shown in Fig. 6 comprises all thatis illustrated in Fig. 5, and, in addition, a currentreducingtransformer has its primary winding 50 connected in series relation withthe armature A1, and its secondary vvwlnding 51 in. series with armatureof the and the field winding tare-A is short-circuited by the switchtorque relay, therebyreducing the current utilized by the relay armatureto anyjdesired value. The contact members 42 are shown as separate, andthe switching device K is shown as normally open, the motor winding,thereby connecting the motor in the doubly-fed relation. It will beunderstood by those skilled in the art that the systems illustrated inFig. 5 and Fig. 6 may be suitably combined, if desired, as is describedin connection with Fig. 8.

The efiect of phase displacement between the armature and field currentmay be compensated for by the use of a relay connected as in Fig. 5, ifthe relay parts are magnetically saturated to the same degree as themain motor, thereby obtaining a torque from the relay that issubstantially exactly proportional to'the motor torque. Where the mainfield voltage is employed to energize the field winding of the relay,the ratio of the saturation may vary from equality.

Referring now to Fig. 8, the system shown embodies an automaticallyoperatin combination of the acceleratm metho s disclosed in Fig. 1, Fig.5 and ig. 6. The system comprises the auto-transformer AT; thesingle-phase motor having armature A and series field windings F and Cthe torque relay T that is connected as in Fig. 5; the switching deviceK and a plurality of switching devices K and K that respectivelyresemble the device K and K but, that, in addition, are provided withinterlocking members T and T of a familiar type for effectingautomatically progressive operation of the switching devices, accordinto the movement of the torque relay T This type of interlockingapparatus is familiar to those skilled in the art of automatic controlsystems, particularly systems for the control of railway motors, and nofurther description thereof is deemed necessary here.

The operation of the system may be briefi set forth as follows: themotor is starts with the various switches in the respective positionsshown, whereby the motor arma- LA and the resistor AR is included in themot r circuit. The auxiliary contact here 42 that are associated withthe torque r initially held open by reason o1 w dominance of the torqueproducer; T"

' moves the drum 43 to effect engagement ofthe contact members 42,thereby completing the energizing circuit of the actuating coil of thedevice K and thus causing permanent short-circuit of the resistor sincethe device K is interlocked in its closed position by means of theholding-circuit connection hereinbefore described.

The rush of current occurrin upon the short-circuit of the resistor Aefi'ects a temporary. disengagement of the contact members 42. When thecontact members again engage by reason of the decrease of motor currentand torque, the actuating coil of the switching device K is energizedthrough the interlock I of the device K, and the motor is thus changedfrom repulsion to series connection. Similarly the switch K issubsequently actuated, according to the movement of the torque relay Tto connect the motor in doubly-fed relation.

Various modifications in the specific circuit connections andarrangement of parts herein set forth may be made within the spirit andscope of my invention, and I desire, therefore, that only suchlimitations shall be imposed as are indicated in the appended claims. c

I claim as my invention:

1. 'In a system of control, the combination with a supply circuit, andan ele'ctric motor having an armature and a series field-magnet winding,said armature being adapted to receive currents of different value fromthose flowing through the field winding, of a main- ;circuit translatingdevice initially connected in circuit with the armature and the fieldwinding of said motor, and means for excluding said translating devicefrom circuit upon a predetermined variation of machine torque.

2. In a system of control, the combination with a supply circuit, and anelectric motor having an armature and a field-magnet winding, saidarmature being ada ted to receive currents of difierent value rom thoseflowing through the field winding, of means included in the circuitof'the armature and of the field winding for automatically changing theamounts of current flowing through the armature and thefield winding vto effect acceleration of the motor,

3. In a system of control, the combination with a supply circuit, and anelectric motor having an armature and a field-magnet winding, of amain-circuit translating device initially connected to the armature andthe field winding of-sa'ld motor, and means influenced in (proportion toboth the annamm and fiel -w1ndingcurrents for automatically excludingsaid device from circuit to efiect acceleration of the motor.

4. In a system of control, the combination with a supply circuit, and anelectric motor having an armature and a field-magnet winding, of a maincircuit translating device initially connected to said motor, and aswitching device having a plurality of actuating coils respective yrtion to the armature and the field-windmg currents and adapted tojointly effect the upon a predetermined variation of motor torque.

5. In a system of control, the combination with a supply circuit, and anelectric motor having an armature and a field-magnet winding, of anauxiliary source of energy connected to said motor to cause a differencein the values of the armature and fieldwinding currents, and meansinfluenced by the electrical conditions of both the armature and fieldwinding to automatically effect acceleration of the motor.

6. In a system of control, the combination with a supply circuit, and anelectric motor having an armature and a field magnet winding, of anauxiliary source of energy connected to said motor to cause a differencein the values of the armature and field-winding currents, a main-circuittransw a switchin device having a plurality of actuating 001 srespectively energized in roortion to the armature and the field-windmgcurrents and adapted to 'ointly efi'ect the actuation of said switchinevice to exclude said translating device 8. In a system of control, thecombination with a supply circuit, and an electric motor energized 1nprorom circuit upon a predetermmed variation of motor tor ue.

having an armature and a field-magnet winding, of a switching device forinitially effecting a predetermined set of connections of the motorwindings, and controlling means for said device influenced in pro ortionto both the armature and field-win in currents for automaticallyactuating sai with a supply circuit, and an electric motor having anarmature and a' field-magnet trolling means for said device comprising atorque relay having an armature and a field winding respectivelyenergized in proportion to the motor armature and field-Winding currentsfor automatically actuating said device to efi'ect another set of motorconnections under predetermined motortorque conditions.

In testimony whereof I have hereunto sub scribed my name this 19th da ofNov., 1914.

RUDOLF E. HLLMUNDQ Witnesses: 2

JOHN. S. DEAN, B. B. HINES.

connections of the motor windings, and com

